'clientIp' can no longer be set with TestClient

The 'client' scope was removed in
encode/starlette#2377, which means we can't read
the client IP from it in unit tests

tests/integrations/test_asgi.py

@@ -139,7 +139,6 @@ async def app(scope, recv, send):
         self.assertEqual('GET', request['httpMethod'])
         self.assertEqual('http', request['type'])
         self.assertEqual('http://testserver/', request['url'])
-        self.assertEqual('testclient', request['clientIp'])
         self.assertEqual('testclient', request['headers']['user-agent'])
 
         exception = payload['events'][0]['exceptions'][0]